[Gmecm] High-voltage P&H IDM

[bcroe at juno.com]

I guess you could try that; hard to say if the saturated 
injectors would respond the way you want.  I wonder 
where you are going to find a mobile 30 VDC supply 
that works over battery (including cranking) and temp.  

Why not just use P+H injectors which run right off 12V?  
Easy for me to say, they are stock on my 79 Eldo.  A 
saturated driver output can be converted by initially 
conducting full power, then inserting a power limiter 
till the pulse ends.  Then reset for the next pulse.  I 
was trying to design one that also increases the peak 
width as battery voltage decreases, haven't got the ideal 
curve yet.  Lets leave microcontrollers out of this; they 
are not too happy in such a hostile environment, and 
not needed for this function.  

Bruce Roe

28 Feb 2006  "David Allen" <davida1 at hiwaay.net> writes:
>   Has anyone made a stand-alone IDM that will take an injector pulse 
> from a
> saturated-driver ECM, and create a peak and hold waveform?  I was 
> thinking
> about making one that would operate high-impedance injectors 
> (normally used
> saturated) in a peak and hold configuration.  The peak voltage would 
> be 30V
> (or thereabout) and the holding duty cycle would be set to create 
> the same
> current flow as the injector at 12VDC. This should improve opening 
> time and
> result in a more linear low-pulsewidth map. I am thinking of this as 
> a way
> to use big injectors on a small turbo engine without idle issues.
>   This would be fairly easy to do with a microcontroller and some 
> power
> electronics.  I figure this has been done before. The 
> direct-injected
> diesels use high voltage IDM's to get their injectors to work 
> efficiently.
>   Any thoughts?
> David
> 
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